class Solution {
public:
    int search(vector<int>& nums, int target) {
		int left=0,right=nums.size()-1;
		while(left<=right)
		{
			int mid=left+(right-left)/2;
			if(nums[mid]<target)left=mid+1;
			else if(nums[mid]>target)right=mid-1;
			else return mid;
		}
		return -1;
    }
};
